Apparatus for the forming of articles



March 29, 1966 o. e. DALTON ETAL 3,242,712

APPARATUS FOR THE FORMING 0]? ARTICLES Original Filed Dec. 4, 1961INVENTORS: EICHAQD K. MAY JESS: L.McDANIEL Y 09AM croN ATTO UnitedStates a tent U i This is a division of US. application Serial No.156,684, filed December 4, 1961, now US. Patent No. 3,187,608, grantedJune 8, 1965.

This invention relates to the forming of articles such as cutting toolsand more particularly, to apparatus for the forming and resizing ofarticles such as cutting tools which are particularly well adapted forutilizing high energy apparatus as force applying means.

It has heretofore been the usual practice to form articles such ascutting tools from stock by machining operations which involve theremoval of a substantial amount of metal in the shaping of the toolcutting teeth and in the defining of other geometrical features of thetool. This procedure is not only wasteful of material but it is alsotime consuming and accordingly expensive. It has the further seriousdrawback of producing articles such as a cutting tool of inferiorstrength and durability. This is the result of grain end exposureoccurring when the cutting teeth are machined transversely of the grainflow of the stock material and is particularly pronounced in the case oftools having helical teeth or helical flute cutters. Sharp corners occurin the change of direction areas of the machining cuts and these cornersact as stress risers in subsequent heat treating of the tools and intool use wherein the tool is called upon to sustain forces actingtransversely of the grain flow, a direction of weaker strength. Thisfurther degradates the physical properties of the tools and theirability to resist shock and fatigue.

The apparatus of this invention has as an objective the provision ofarticles such as cutting tools, particularly those adapted for shank andarbor mounting, which eliminate the above undesirable characteristics ofmachined tools by forming the tools so that the grain flow generallyparallels the cutting teeth, reducing areas of stress. rise, presentingmaximum strength in the direction of these stresses sustained duringcutting operations and thereby producing greater resistance to chippingof the cutter teeth. It should be noted that the teachings of thisinvention have applicability both to the initial forming of articlessuch as cutting tools and to their resizing after use. The apparatuscontemplates forming of the articles such as cutting tools oversize,with grinding generally necessary only to eifect close tolerancemounting surfaces and the clearance angles of article geometry. Anarticle is in effect, born to shape, With a minimum requirement forsubsequent removal of material. No grain ends appear along the surfacesof the cutting teeth and a continuous grain fiow is produced in areaswhere there occur changes in the geometry of the article. In addition toorienting the grain of the article material for maximum effectiveness,the invention provides an article with a refined granular structure,thus improving the article strength characteristics.

In addition to the above, the invention has as an object the provisionof an apparatus which will permit the ready forming of a wide variety ofmaterials which are difficult or impossible to satisfactorily machine.

A further object is the provision of an apparatus which is adapted toutilize high energy rate force-imparting means to achieve excellentmaterial flow and accurate extrusion forming.

3,242,7l2 Patented Mar. 29, 1966 Another object of the invention is toprovide apparatus of simple and rugged structure which is capable ofsustained operation to produce improved articles such as cutting toolsat a reduced cost of material, time and manhours.

Other objects and advantages of this invention will become apparent fromthe following description when taken in conjunction with the drawings,in which:

FIGURE 1 is a plan view of an embodiment of the apparatus with the dieshown in horizontal section, the punch being illustrated by way of solidoutline in a retracted position prior to reception within the die, andby means of broken line outline after extension and reception within thedie to induce forming of the cutter blank.

FIGURE 2 is a view similar to that of FIGURE 1, with the cutter blankshown after formation and during ejection from the die by the ejectormeans.

FIGURES 3 and 4 are views in side elevation, respectively showing toolsconventionally formed by machining, and by the apparatus and process ofthis invention, the arrows indicating the direction of grain flow ineach tool.

FIGURE 5 is a view in horizontal section of the apparatus of theinvention utilized in resizing used cutter tools.

Generally described, the illustrated embodiment of the inventioncontemplates the forming of cutting tools or cutters having helicallyshaped teeth by means of a punch receivable within a helically fluteddie cavity. The die cavity, which is somewhat oversize to permitgrinding of the cutter blank to final size, is open to reception of thepunch on one end, and is closed by means of an ejection or knockout toolat the other end. This tool is provided with one or more ribs or threadsof helical shape similar to and mateable with the die cavity flute orflutes. For the forming operation, the ejection means or tool ispositioned within the die to effect its end closure, thereby todetermine the length of the cutter blank and its end configuration.Subsequently the ejection means serves to eject the formed cutter toolblank from the die as it twists through the die cavity. High energy rateapparatus have been found particularly satisfactory as driving means forthe punch. By high energy rate apparatus is meant apparatus capable ofapplying a force of from approximately 100,000 to 300,000 psi. at aninitial velocity of approximately 740 inches per second. It is importantthat the billet of metal moving through the die under influence of thepunch be extrusion-formed in order to achieve the aforementionedsalutary grain flow. Heating of the billet prior to forming is effectedto aid in achieving this fiow. As extruded, the cutter tool blankrequires but a minimum of additional Work, as by guiding, to shape itscutting tip and shank geometry, the latter to satisfy the requirementsof the particular cutting tool application desired. This grinding can befurther assisted by suitably shaping a protuberance on the end of thetool, as will be mentioned hereinafter.

After use, cutter tools become worn and chipped. Regrinding toreshairpen the tool causes a reduction of the tool diameter. Since thetolerance With respect to this diameter is often critical, particularlythe case of rogrammed automatic milling machines, the cutters becomeunusable after a limited number of grinding operations. However, throughpractice of the teachings of this invention, these unusable cutters maybe resized and again made usable. The process involves heating the usedcutter tool and placement of same in a die having a cavity shaped todefine the desired cutter tool configuration. Punch means are forced bytram means against the heated cutter tool positioned Within the die toeffect its upset and an increase in the tool diameter to that of the diecavity, which latter is sufficiently oversize to permit subsequentgrinding of the blank to produce the finished cutter. Approximately thesame amount of grinding after the formation of the blank is required tofinally shape the tool as is required incident to initial make-up of thecutter tool, generally described above.

Turning now to the drawing and a detailed description of the invention,there is shown in FIGURE 1 a die, generally designated by the numeral 6,-comprised of a bolster plate 8 upon which a die block 10 is mounted bymeans of a hold down plate 12 and attachment bolts 14, only one of whichis illustrated. Die block 10' is provided with an axially disposedcavity 16 of slightly greater dimension than the final cutter and havinga first or outer portion 18 of generally smooth bore and a second orinner portion 20 having a pair of helically shaped flutes 22. As isillustrated in FIGURES 1 and 2, die 6 is so mounted upon bolster plate 8as to axially align die cavity 16 with a smooth bore cavity 24 which isprovided in the bolster plate and which is of greater diameter than thedie cavity. The die block should of course be made of a high qualitytool steel and the remaining die parts of a high strength toughmaterial. It should be understood that the die 6 may assume a variety ofconfigurations insofar as hold down plate 12 and the externalconfiguration of the die block 10 are concerned. It is, however,important that the cutter tool forming cavity be generally aligned withthe cavity 24 provided in the bolster to permit the indicated travel ofthe knock-out tool.

In FIGURE 1 the punch means, generally designated 26, is shown mountedupon force-imparting actuating means 28, which latter is preferably ahigh energy r-ate ram capable of driving the punch means at a velocityof approximately 740 inches per second and of imparting a pressure tothe billet undergoing extrusion of from approximately 100,000 to 300,000p.s.i. As shown in FIG- URE l, actuating means 28 and punch means 26 areretracted. Punch means 26 is comprised of a cylindrically shaped stopblock 30 which embraces the end of elongated cylindrical punch 32, thelatter carrying at its exposed extremity a protuberant punch tip 34 ofconvex shape. Provision of the tip 34 is optional; however, it is usefulin the subsequent grinding operation, as will presently be explained.

A knock-out tool 36, serving as the formed cutterblank ejection means,is disposed for axial movement through aperture 24 and die cavity 16,being provided with a pair of ribs or threads 33 shaped helically tomate with the similarly shaped pair of fiutes 22 in the die cavity. Thethreads 38 permit the tool to twistably move through the cavity from theposition of die cavity closure and cutter-blank forming of FIGURE 1 tothe position of ejection of the completed cutter-blank 40 shown inFIGURE 2.

It is important that the inner end of the die cavity be closed duringforming of the cutter-blank 40 and therefore that the knock-out toolribs 38 be received in rather close fitting relationship within theflutes 22, at least at the outer face of the knock-out tool in the areaof cutterblank end forming. Because of the high pressures built upduring forming, die fracture may be a problem. Such fracture may,however, be prevented by permitting a metered fiow of the pl-asticizedbillet material past the knock-out tool 36 intermediate the cavityflutes and the mating knock-out pin threads. A cavity 42 offirustoconical shape may be provided at the outer or cavity closing endof the tool for the forming of a protuberant portion upon the cuttertool to facilitate grinding to final shape. Further, inasmuch as forcesagainst the knockout pin will develop compressive stress therein, thenonforming end of the pin may be expanded in design to reduce thesecompressive stresses. Actuating means (not shown) serve to move the tool36 through aperture 24 and die cavity 16.

Describing now the operational steps of forming the cutters, a billet 44is made up from round bar stock of suitable diameter. Good results havebeen obtained using T-1 high speed tool steel the composition of whichis as follows: carbon, .72%; manganese, 25%; silicone, 20%; tungsten,18.25%; chromium, 4.00%; and vanadium, 1.15%. Other suitable materialsmay, however, be used. The billet should be of a volume somewhat greaterthan that of the finished cutter tool in order to allow for finishgrinding, including removal of protrusions at the inner end of thecutter. The diameter of the billet should be sufiicient to assureextrusion forming of the billet in order to achieve the beneficial grainflow heretofore mentioned. By extrusion forming is meant the forcing ofbillet flow under sufficient pressure and with sufficient speed toachieve plastic flow of the billet material through the fluted diecavity to impart to the billet cutter teeth of :a helical shape similarto the shape of the cavity fiutes. This is well provided through use ofhigh energy rate ram actuating means for the punch. It is preferablethat the billet be suitably heated to a point below its melting point torender the material susceptible to plastic flow and extrusion forming.For T-l steel, maximum billet pre-heat will range from about 2100 toabout 2350 F. To further facilitate forming, it is preferable that a dielubricant be used and for this purpose silicone base lubricants havebeen found satisfactory.

As shown in FIGURE 1, the heated billet 44 is placed in the die blockcavity 1% with the knock-out tool 36 positioned as indicated to closethe cavity, defining the length of the cutter blank and its endconfiguration. The die may be heated if the die material is of a hotworked type tool steel; but this is optional. Where heated, a preferredtemperature range is from 400 to 700 F. However, forming of the billetshould be undertaken immediately after billet heating in order that thebillet not be substantially cooled by conduction of heat through the dieand away from the billet. The high velocity rammeans utilized hereinfacilitates the needed rapid application of a forming force prior tosuch billet cooling.

In forming the billet 44, the ram forces the punch inwardly at highvelocity for reception within the die cavity 16 and impact with thebillet. As already indicated, it is desirable that the ram actuatingmeans he of a high energy rate type. For the forming of cutter toolsfrom T1 steel, excellent results have been achieved using ram meanscapable of an energy output of approximately 538,000 in./lb. Forming wasaccomplished using a total ram stroke of 11 inches, including the metalworking or billet forming stroke which was approximately 2 inches. Theenergy at contact was approximately 497,000 in./l-b. with the ram andpunch moving at an approximate velocity of 740 inches per second. Totalweight of the ram, punch and the moving parts and weights associatedtherewith, was approximately 770 lbs. The high energy rate ram actuatingmeans assures excellent plastic flow of the billet material during theforming operation, which terminates as the punch means moves into theposition shown in FIGURE 1 in broken outline, with the stop block 30abutting the outer surface of hold down plate 12. An outwardly flaredaperture 46 is provided in plate 12 to receive the enlarged end portionof punch means 26. As the billet 44 is forced through the die cavity, itis extrusion-formed in the fluted second or inner cavity portion 20 todefine the helical cutting teeth 48. The length of the cutter blank, aswell as its cutting end configuration, is defined by the knockout tool36, the cavity 42 therein serving to shape a frusto-couical protuberance50 in the cutting end. That portion of the billet filling the innerportion 18 of the die cavity defines the smooth wall cylindrical shankportion of the cutter and the punch tip 34 forms a concavity 54positioned axially of the shank outer end. Upon completion of theforming operation, the punch means is retracted and the formed cutterblank is cooled to permit its ejection from the die cavity which latter,as shown in '5 FIGURE 2, is accomplished by means of the knock-out tool36. Thus tool 36 is caused to twistably move through the die cavity 16with guidance provided by ribs 48 tracking in die flutes 22.

In FIGURE 2, the cutter blank 40 is shown in a position ready forremoval from the die and subsequent grinding to final shape. The cutterblank is also shown in FIGURE 4 in a similar state ready for finalgrinding. Such grinding is accomplished utilizing the axially disposedconcavity 54 and the protuberance 50 located at opposite ends of theblank. The protuberance 50 not only facilitates the grinding operationbut permits shaping of the cutting end of the cutter merely by theremoval of a minimum .amount of material. Concavity 54 may assume avariety of shapes depending upon grinding re quirements and ultimatemounting requirements for the use of the finished cutter.

FIGURES 3 and 4 respectively present a comparison between the grain flowin cutters formed by conventional machining methods and by the method ofthis invention. A conventional cutter 56 is illustrated as havinghelical cutting teeth 58 in its cutting portion 60 .and a notched shankportion 62 for mounting of the cutter, as in a milling machine. Thearrows 64 and 66 upon the cutting portions of each of the cutters 40 and56 indicate the direction of grain flow. It is readily apparent that thesharp angular corners with attendant grain end exposure and stress riseare virtually eliminated in the cutter tools produced by this invention,being replaced by a smooth granular flow paralleling the direction ofthe helical cutter teeth 48.

In FIGURE is shown the apparatus used to re-size cutters after use. Thisapparatus is identical with that shown in FIGURES 1 and 2, except forthe enlarged protuberant tip 68 provided at the exposed extremity of aslightly modified punch 70 and the knockout tool 72 shaped at its inneror forming end 74 to mateably receive the cutting tip of the used cuttertool 76. The cavity provided within die block is of somewhat greaterdimension than the finished cutter tool 76 to permit grinding of thetool to final dimension after resizing. The used tool 76 will of coursebe considerably smaller than the cavity, depending upon the amount ofwear. The punch tip 63 serves to displace material from the shank end ofthe used cutter tool causing tool material to flow outwardly intoconformity with the die cavity walls. The size of the tip willaccordingly vary with the extent of wear of the tool and the amount ofmetal displacement required. In any event, the cutter blank is formedsomewhat oversize to permit of subsequent removal of material bygrinding to achieve the final cutter geometry.

In resizing, the used cutter tool 76 is first heated to a temperaturejust below its melting point and sufiiciently high to render the cuttertool material plastic and susceptible to flow within the die. The heatedtool 76 is then placed within the die 10, heating of which latter isoptional. The punch is thereupon immediately impacted against theplasticized cutter tool before the latter cools, the tool being forcedinto conformity with the die cavity walls by the displacing action ofthe tip 68. A high energy punch or ram means is preferably employed ineffecting the resizing of the used cutter tool. After the formingoperation is completed, the punch is withdrawn from the die and theresized cutter tool is allowed to cool. Removal is then etfected in themanner previously described for the forming of new cutter tools, withthe knockout tool spiralling outward to force the cutter blank from thedie. The blank is finally ground to a finished configuration in themanner described above for the initial forming of .a cutter tool, withthe exception that a lesser amount of material will be removed from thecutter tool cutting extremity as a result of the proximity of the shapeof the resized cutter to that of the cutter tool ultimate shape.

Although the invention has been described with respect to certain of itspreferred embodiments, it is to be understood that it may be altered,changed or modified within the scope and spirit of the appended claims.

We particularly point out and distinctly claim as our invention:

1. An apparatus for the forming of cutters having helical teethcomprising, in combination:

a die having a cavity therein for the receipt of a billet, at least aportion of the side wall of said die cavity being provided with ahelical flute for cutter tooth forming;

punch means actuable by high energy rate ram means and receivable withinsaid die cavity to extrude a billet positioned therein to form a cutterblank; and

an ejection member movable through the cavity to eifect substantialclosure of one end of said cavity and provided with a guiding thread ofa helical shape similar to that of said flute, said guiding thread beingreceivable within the helical flute to track therein causing saidejection member to move in rotation as same moves longitudinally of saidcavity thereby to eifect rotational and longitudinal movement of theextruded billet and its ejection from the die cavity.

2. An apparatus for the forming of cutters having helical teethcomprising, in combination:

a die having a cavity therein for the receipt of a billet, at least aportion of the side wall of said die cavity being provided with ahelical flute for cutter tooth forming;

punch means actuable by high energy rate ram means and receivable Withinsaid die cavity to extrude a billet positioned therein to form a cutterblank;

stop means for limiting the movement of the punch means relative to thedie in the extrusion of said billet; and

an ejection member movable through the cavity to etfect substantialclosure of one end of said cavity and provided with a guiding thread ofa helical shape similar to that of said flute, said guiding thread beingreceivable within the helical fiute to track therein causing saidejection member to move in rotation as same moves longitudinally of saidcavity thereby to effect rotational and longitudinal movement of theextruded billet and its ejection from the die cavity.

3. An apparatus for the forming of outters having helical teethcomprising, in combination:

a die having a cavity therein for the receipt of a billet, at least aportion of the side wall of said die cavity being provided with ahelical flute for cutter tooth forming;

punch means actuable by high energy rate ram means and receivable withinsaid die cavity toextrude a billet positioned therein to form a cutterblank; and

an ejection member movable through the cavity and provided with .aguiding thread of a helical shape similar to that of said flute, saidguiding thread being receivable within the helical flute to tracktherein causing said ejection member to move in rotation as same moveslongitudinally of said cavity, the ejection member thereby initiallyserving to define the end of the die cavity and the extent of the billetextrusion and thereafter serving to effect rotational and longitudinalmovement of the extruded billet and its ejection from the die cavity.

4. The apparatus of claim 3, wherein spacing is provided between saidflute and said helical thread received therein to provide pressurerelief during billet extrusion.

5. An apparatus for the forming of cutters having helical teethcomprising, in combination:

a die having a cavity therein comprised of a first portion havingsubstantially smooth walls and a second portion having a flute ofhelical shape formed in its side wall for the extrusion forming of acutter tooth; punch means receivable within said die cavity to abut saidbillet to extrude same within said die cavity to form a cutter blank;and an ejection member movable through the cavity and provided With aguiding thread of a helical shape similar to that of said flute, saidguiding thread being receivable within the helical flute to tracktherein causing said ejection member to move in rotation as same moveslongitudinally of said cavity to effect cavity closure and, with thepunch, definition of the extremities of the extruded billet and therebythe extent of billet extrusion. 6. The apparatus of claim 5, whereinsaid flute is of a larger cross-sectional dimension than said helicalthread thereby to permit metered flow of material from said billetintermediate the flute and the thread received therein to providepressure relief during billet extrusion.

7. Apparatus for forming from a billet of material articles having acontinuous grain flow in areas having various geometric configurationscomprising a die, movable means operatively mounted with respect to saiddie to variably define the length of the die and to define asubstantially closed end thereof, and means for extruding materialWithin said die toconform to substantially the configuration of theportion of said die intermediate said movable means and said extrudingmeans, said movable means additionally functioning to eject the formedmaterial from the die.

8. Apparatus for forming articles having various geo metricalconfigurations from a billet of material comprising: a die block havinga die cavity therein, means for supporting said die block, means forretaining said die block with respect to said supporting means, movablemeans operatively mounted with respect to said die block cavity todefine a movable substantially closed end therefor, and means adapted toform a billet of material in the cavity of said die block to essentiallyconform with the configuration of said die cavity intermediate saidforming means and said movable means, said movable means being adaptedto move Within said die block cavity to variably define the volume ofthe cavity and to force out material therein.

9. The apparatus defined in claim 8, wherein said billet forming meanshas a velocity capability of at least 740 inches per second andcapability to impose upon the associated billet of material a pressureof at least 300,000 psi.

10. The apparatus defined in claim 8, wherein said billet forming meansincludes a protruding portion which functions to form a concavity in theassociated billet.

11. The apparatus defined in claim 8, wherein said billet forming meansincludes a stop means therefor.

12. Apparatus for forming from a billet of material articles having acontinuous grain flow in areas having various geometric configurationscomprising a die having a cavity therein adapted for receiving a billetof material to be formed, at least a portion of said cavity having ahelical configuration, movable means operatively mounted with respect tosaid die to define a substantially closed end thereof, said movablemeans also functioning to vary the length of said cavity, means adaptedfor extruding the material Within said die to conform to substantiallythe configuration thereof, said extruding means including a protrudingportion which functions to form a protuberance in the associated billetof material, said movable means additionally functioning to eject formedmaterial from the die.

13. Apparatus for forming articles having various geometricalconfigurations from a billet of material comprising: a die block havinga die cavity therein, said die block cavity including a helica-llyconfigured portion, means for supporting said die block, means forretaining said die block with respect to said supporting means, movablemeans operatively mounted with respect to said die block cavity todefine a movable substantially closed end therefor, said mo'vable meansbeing provided with a configuration such as to cooperate with saidhelically configured portion of the die block cavity, and means adaptedto form a billet of material in the cavity of said die block toessentially conform with the configuration of said die cavityintermediate said forming means and said movable means, said formingmeans being adapted to cooperate with a portion of said die cavity tosubstantially prevent material from being extruded between said formingmeans and said die cavity portion, said movable means being adapted tomove within said die block cavity t define the volume of the cavity andto force out material therein.

References Cited by the Examiner UNITED STATES PATENTS 2,345,100 3/1944Cotton 76-108 2,748,464 6/1956 Kaul 2076 1 2,764,042 9/1956 Gotze 761082,904,173 9/1959 Braun et al. 207-6 2,954,121 9/1960 Benson 20762,966,987 1/1961 Kaul 2076.1

CHARLES W. LANHAM, Primary Examiner.

E. D. OCONNOR, Assistant Examiner.

1. AN APPARATUS FOR THE FORMING OF CUTTERS HAVING HELICAL TEETHCOMPRISING, IN COMBINATION: A DIE HAVING A CAVITY THEREIN FOR THERECEIPT OF A BILLET, AT LEAST A PORTION OF THE SIDE WALL OF SAID DIECAVITY BEING PROVIDED WITH A HELICAL FLUTE FOR CUTTER TOOTH FORMING;PUNCH MEANS ACTUABLY BY HIGH ENERGY RATE RAM MEANS AND RECEIVABLE WITHINSAID DIE CAVITY TO EXTRUDE A BILLET POSITIONED THEREIN TO FORM A CUTTERBLANK; AND AN EJECTION MEMBER MOVABLE THROUGH THE CAVITY TO EFFECTSUBSTANTIAL CLOSURE OF ONE END OF SAID CAVITY AND PROVIDED WITH AGUIDING THREAD OF A HELICAL SHAPE SIMILAR TO THAT OF SAID FLUTE, SAIDGUIDING THREAD BEING RECEIVABLE WITHIN THE HELICAL FLUTE TO TRACKTHEREIN CAUSING SAID EJECTION MEMBER TO MOVE IN ROTATION AS SAME MOVESLONGITUDINALLY OF SAID CAVITY THEREBY TO EFFECT ROTATIONAL ANDLONGITUDINAL MOVEMENT OF THE EXTRUDED BILLET AND ITS EJECTION FROM THEDIE CAVITY.